Please refer to FIG. 1, which is a schematic diagram showing a flashlight with a light-focusing function according to the prior art. Lights are emitted from a light source 1, and then are controlled by a lens set 2. Despite by the light-focusing capability of the lens set 2, the focal position of the lights can be changed by controlling the distance between the lens set 2 and the light source 1, i.e. the focal position at the light axis, so as to control the degree of light illumination at a specific position at the light axis. In other words, one may choose to utilize the lens set 2 to let the lights be focused at a location where a higher degree of illumination is needed, and vice versa.
Please refer to FIG. 2, which is a schematic diagram showing another type of flashlight with a light-focusing function according to the prior art. Compared to the type of deflection adopted in FIG. 1, the type of flashlight illustrated in FIG. 2 reflects the lights from the light source 1 to a specific direction by a reflection mirror 3. According to the apparatus shown in FIG. 2, one may choose to allocate the light source 1 at a focus (not shown) of the refection mirror 3 to have the reflected lights be more focused at a smaller area. On the contrary, one may choose to move the light source away from the focus of the refection mirror 3 to let the reflected lights illuminate a broader area.
Please refer to FIG. 3, which is a schematic diagram showing a light-projecting system according to the prior art. In general, lights are emitted from a light source module 10, pass through a deflective zoom module 20, which includes solid or liquid lens to control the projection angle (not shown) of the lights, and illuminate an object 4. Usually the smaller projection angle, the smaller the illuminated area and the higher degree of illumination at the object 4, and vice versa.
Please refer to FIG. 4, which is a schematic diagram showing a two-dimensional photo mask employed in a light-shaping device according to the prior art. A mask 5 is disposed in front of a flat light source 100 to control the shape of the lights. Due to the flat light source 100, the light intensities at different locations of the mask are the same in theory. If there is a specific shape opened on the mask 5, says an open area having a shape of cross 5′, the shape of cross 5′ will then be projected on the object 4. The light-shaping device illustrated in FIG. 4 is convenience for use. However, it needs a lot of masks 5 when several types and shapes of lights are needed, which could end up with a very large size of the light-shaping device for controlling a whole optical field. Besides, the fact that a large portion of lights are blocked by the mask 5 results in wasteful in terms of energy consuming. Without a zoom device, the shape of cross 5′ produced by the light shaping device as illustrated in FIG. 4 is bigger when the distance between the object 4 and the mask 5 is larger, while the degree of illumination thereof decreases. It will be hard to control the dimension of the shape of cross 5′.
Please refer to FIG. 5, which schematics a light source array device. The flat light source array 100 consists of plural light emission device 10a. It can be observed that the flat light source array 100 is a square array from a front view. For a more dense alignment, a honeycomb array is also applicable. A specific light shape can be achieved by selectively illuminating some of the light-emitting devices. However, it is hard for the light source array illustrated in FIG. 5 to control the illumination and the size of the specific light shape without a zoom device.
According to the above-mentioned, there is a need to develop an optical device for controlling a three-dimensional optical field. The optical device is able to generate a specific light shape without a mask, and control the degree of illumination as well as the size of the light shape.